Writing in Threes

The power, the magic, and the charm of three

Anecdotal evidence suggests that when trying to persuade, presenting three concepts is better than presenting two. Or four. Or more. We see examples of memorable, powerful threes in advertising, in literature, and even in the Declaration of Independence:

  • snap, crackle, and pop
  • I came; I saw; I conquered
  • life, liberty, and the pursuit of happiness

Yes, I just gave three examples.

Do you have a sense of the importance of three in writing? Did you ever learn to write a “five-paragraph essay”? You present an introduction and a conclusion, but in between you write the first point, the second point, and the third point. The power of three.

When creating lists, when presenting claims, or when organizing arguments, writing in threes is common advice from legal-writing experts. Patrick Barry says, “Judges use the Rule of Three. Practitioners use the Rule of Three. And so do all manner of legal academics.”[1] Diana Simon advises that when possible, “distill your arguments down to three main points … and, if possible, eliminate arguments after that point .…”[2] And Bryan Garner reports that “A mathematician once told me that there are really only four numbers in the world: one, two, three, and many.[3]

But is the persuasive power of three anything more than good advice? Yes. Empirical studies validate the “magic of three,” as Diana Simon summarized in a recent article.”[4]

In one study, subjects learning a new word were better able to understand and apply the word’s meaning after being given three examples.[5] Similar research suggests that we consider evidence and examples to establish a pattern or a “streak” once they hit three.[6]

In another study, subjects described getting back together with an ex-partner, and the descriptions had from one to six reasons that the renewed relationship was good. In one scenario, the person described the ex-partner with four words: “intelligent, kind, funny, and cute.” Researchers noticed that the fourth word provoked skepticism in listeners, and overall, those who heard three positive traits were more likely to approve of the relationship than those who heard four.[7] The authors of that and other studies concluded that “the optimal number of claims is three ….”[8]

In the real world, you can’t always force legal standards into threes. After all, premises liability in Texas has four elements. But if one element is beyond dispute or if one has been waived or stipulated, your memo, motion, or brief can present the three remaining elements. Or maybe for the fourth element is supported by three arguments or three key pieces of evidence.

Would using some examples help you present your position? If so, consider using one or three, but not two—and definitely not four: remember the power of three. And when constructing sentences, if you have the opportunity to present parallel ideas, phrases, or clauses, see if you can reasonably present them in threes. So this:

  • The employer’s responses were hasty, terse, superficial, and disrespectful.

Is likely not as powerful as this:

  • The employer’s responses were hasty, terse, and superficial.

When you can, take advantage of the power of three.


[1] Patrick Barry, The Rule of Three, 15 Legal Comm. & Rhetoric 247, 247–48 (2018).

[2] Diana J. Simon, The Power of Connectivity: The Science and Art of Transitions, 18 Leg. Comm. & Rhetoric: JALWD 65, 80 (2021).

[3] Bryan A. Garner, Good Headings Show You’ve Thought Out Your Arguments Well in Advance, ABA J. (2015), https://www.abajournal.com/magazine/article/good_​headings_​show_​youve_​thought_​out_​your_​arguments_​well_​in_​advance/

[4] Simon, The Power of Connectivity, at 76-77.

[5] Simon, The Power of Connectivity, at 77 citing Suzanne B. Shu & Kurt A. Carlson, When Three Charms but Four Alarms: Identifying the Optimal Number of Claims in Persuasion Settings, 78 J. Marketing 127, 137 (2014) citing J.B. Tenenbaum & F. Xu, Word Learning as Bayesian Inference, Psychol. Rev., 114(2), 245–72 (2000).

[6] Kurt A. Carlson & Suzanne B. Shu, The Rule of Three: How the Third Event Signals the Emergence of a Streak, 104(1) Org. Behav. & Hum. Decision Processes 113 (2007).

[7] Shu & Carlson, When Three Charms, as reported in Susannah Jacob, The Power of Three, N.Y. Times (Jan. 3, 2014), https://www.nytimes.com/2014/01/05/fashion/Three-Persuasion-The-Power-of-Three.html

[8] Id. at 138.